FAA investigating how one Airbus A-320 flew about 120 metres under another in the wrong airspace before air traffic realized its mistake.

Houston Airport was the scene of a near-miss involving a Vancouver-bound United flight on May 9 that the U.S. authorities are investigating.

By:Thestar.com Published on Fri May 23 2014

A Vancouver-bound United Airlines flight taking off from Houston airport flew about 120 metres under another plane and U.S. aviation authorities are investigating.

United Flight 601, the airline’s daily Houston-Vancouver run, veered into the wrong airspace on another runway and skimmed near United Flight 437 en route to Mexico City, the Federal Aviation Administration said Friday.

The tower had advised Flight 601 to turn right when it should have turned left, Houston TV station KHOU reported, quoting a conversation retrieved from Live Air Traffic’s recordings.

“You all basically crossed directly over the top of each other,” a pilot is quoted as saying on the recordings.

“It was pretty gnarly looking,” another pilot replied.

The air traffic controller noticed Flight 601 was heading into airspace reserved for planes on other runway, where Flight 437 had just taken over.

The planes were 1.4 kilometres away in distance and at altitudes 120 metres apart at their closest point, the FAA said in a statement sent to the Star.

The controller then told the pilots to “safely separate the aircraft,” which they did immediately, the FAA said. The planes, both Airbus A-320s, continued their journeys.

The near miss happened at 9:38 p.m. local time, the FAA said.

“The FAA has taken steps to prevent any similar occurrences in the future,” the U.S. agency said.

“Both United aircraft were operating in compliance with their Air Traffic clearances,” United Airlines spokeswoman Jennifer Dohm told the Star.